International Business Machines Corporation

Robert H Farrell

Jerry D Dixon

Gerald U Merckel

Neil A Katz

Andrew B McNeill

William Garrett Verdoorn, Jr

Ernest D Baker

Hernando Ovies

Gerald A Marazas

Peter B Bandy

Francis R Koperda

Jack D Neely

Stephen A Schmitt

An I/O controller for a computer system having a plurality of memory devices of different types such as floppy and hard disks, whereinn a single cache memory is employed for all of the memory devices. Each of the memory devices is provided with its own interface device which directs data outputted from the associated memory device onto a common device bus. From the device bus data is transferred to a cache memory via a separate cache bus, and then to a system processor via the same cache bus. Memory space within the cache memory may be allocated among the various memory devices.

I/O controller for multiple disparate serial memories with a cache

A redundant error-detecting addressing code for use in a cache memory. A directory converts logical data addresses to physical addresses in the cache where the data is stored in blocks. The blocks are expanded to include redundant addressing information such as the logical data address and the physical cache address. When a block is accessed from the cache, the redundant addressing is compared to the directory addressing information to confirm that the correct data has been accessed.

Redundant page identification for a catalogued memory

A method and apparatus for performing data base searches in which the host processor and main memory are free for other processing tasks between the time that the host processor requests the search until the search results are reported back to the host processor. To commence the search, an input/output controller communicates from the host processor to a record scan circuit values of a skip length, a key length and a data length. While data records are received serially from disk files, within each data record, a length of data equal to the specified skip length is initially skipped. Following this, a search argument is compared with a length of data specified by the key length value. This comparison operation is alternated with skipping of data specified by the data length value until the end of the record is reached or until a specified number of comparisons has taken place. The data record is stored as it is received from the files. If a successful comparison is found within a data record, either the entire data record or a specified portion thereof can be read back through the controller to the host processor.

Associative file processing method and apparatus

Serial storage interface apparatus for coupling a serial storage mechanism, such as a charge coupled storage device or a magnetic bubble storage device, to a data processor input/output (I/O) bus. Speed control circuitry is provided for causing the serial storage mechanism to operate at a higher speed when the data processor is responding more rapidly to data transfer requests from the interface apparatus and at a lower speed when the data processor is responding less rapidly to data transfer requests from the interface apparatus. This speed adjustment feature reduces the amount of data buffering required for interfacing a serial storage mechanism to an asynchronous variable response time I/O bus system.

Serial storage interface apparatus for coupling a serial storage

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Coral Springs, FL, United States of America

Robert H Farrell